A converter system includes a switch adapted to be coupled to an inductor, and configured to switch between first and second states responsive to a loop control signal. Calibration circuitry is configured to operate in first and second control modes, provide a calibration voltage in the first control mode, and store the calibration voltage in the second control mode. In a first instance of the first control mode, the calibration voltage is based on a difference between a feedback voltage and a reference voltage. In a second instance of the first control mode, the calibration voltage is the stored calibration voltage from the second control mode. A comparator is coupled to the switch and the calibration unit, and is configured to provide the loop control signal based on a combination of at least the feedback voltage, the reference voltage, the calibration voltage, and a periodic signal.